Is two-party politics on the wane again in Britain?

It may not be a consistent trend, but it is a clear overall trend: the combined vote share of Conservatives and Labour has been steadily falling since the 2017 general election. Two-party politics, after a previous resurgence, looks to be on the wane again.

One contributor to that change is the gradual rise in Liberal Democrat support, now almost but not quite consistently in double figures. This means Lib Dem support in the polls is now, save for a post-Richmond Park bump, now at its highest level since the 2015 general election.

If the party were to regularly hit 11% in the polls, this would make for the best performance since autumn 2010, a brief blip in March 2013 aside. That both says something about the quiet progress the party has been making recently, and also about just how long the period of single figures or close levels of support in the polls for the Liberal Democrats has now gone on for. (A reason why I so regularly make the case that the party needs to change to recover.)

As ever, for a full set of voting intention polls going all way back to the 1940s, take a look at PollBase.